Question 4. An austenitized 4340 standard steel bar is cooled at different rates (see Figure 2).Predict what will be the constituents in the microstructure of the bar at 200°C for

the following cooling rates:(6 points) (a) 5°C/s (51-mm from the quenched end of a Jominy bar) (b) 8°C/s (19.0-mm from the quenched end of a Jominy bar) (c) 50°C/s (9.5-mm from the quenched end of a Jominy bar)